Self-adjusting toggle clamp



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Jan. 15, 1957 Filed Oct. 27, 1954 J. J. SENDOYKAS SELF-ADJUSTING TOGGLE CLAMP 2 Sheets-Sheet l AZ J7 INVENTOR. fie} Z 66714 012 45.

Jan. 15, 1957 J, J, $ENDOYKAS 2,777,347

SELF-ADJUSTING TOGGLE CLAMP 2 Sheets-$heet 2 Filed Oct. 27, 1954 INVENTOR.

Jav? J Sern/oyias'.

BY w, aw.

- rok/vz/s United States Patent SELF-ADJUSTING TOGGLE CLAMP Jack J. Sendoykas, Grosse Pointe Park, Mich.

Application October 27, 1954, Serial No. 465,005

15 Claims. (Cl. 81-84) This invention relates to new and useful improvements in clamping devices.

The device of this invention may assume a number of different forms, as for example, a toggle pliers, a pump jig, a pipe wrench or a clamping fixture. Regardless of its form, however, the device has the advantage of clamping a workpiece automatically and securely and in such a manner that the clamping members or jaws adapt themselves automatically to different sizes of workpieces within the operating range of the device. No manual adjustment of any part is required in order to adapt the clamping jaws to different sizes of workpieces, and a uniform clamping pressure is. obtained at all times regardless of the size of the work engaged by the jaws. When clamped, the jaws are locked securely to thereafter prevent inadvertent release of the work. It has a special feature of the invention that the device, regardless of its form, can be manufactured relatively inexpensively for sale to the trade.

In the drawings forming a part of this specification and wherein like numerals are employed to designate like parts throughout the same,

Figure 1 is a side elevational view of a toggle pliers embodying the invention and showing the jaws clamped on a workpiece;

Fig. 2 is a view similar to Fig. l but showing the jaws open;

Fig. 3 is a View similar to Fig. 1 but showing the jaws clamped together with no workpiece therebetween;

Fig. 4 is an enlarged, transverse sectional View taken on the line 4-4 of Fig. 1;

Fig. 5 is an enlarged, fragmentary, transverse sectional view taken on the line 5-5 of Fig. 2;

Fig. 6 is a fragmentary, longitudinal sectional view taken on the line 66 of Fig. 5;

Fig. 7 is a side elevational view showing a clamping fixture embodying the invention and illustrating the clamping jaws ofthe fixture open and released from a workpiece, and

Fig. 8 is a view similar to Fig. 7 but showing the clamping jaw engaged with the workpiece.

Figs. 16 show the principles of this invention embodied in a toggle pliers having a pair of cooperating jaw members 10 and 12 connected by a pivot 14. A fixed handle 16 is connected to the jaw 10, and a movable handle 18 is fastened to the jaw 12 by a pivot 20. The jaw 10 and fixed handle 16 preferably are made in one piece; and, in the form of the invention shown, the jaw and handle assembly are made from a single piece of sheet metal by conventional stamping and forming operations. More specifically, the sheet metal forming the jaw and handle assembly is bent along the length thereof into a generally .lJ-shape in transverse section to provide opposite side flanges 22 and 24. The ,comp-anion jaw member 12 may be a cast element having a laterally extending lug portion 26 disposed between the flanges 22 and 24, and the pivot 14 is suitably fastened to the flanges to support the jaw member 12 for rocking 2,777,347 Patented Jan. 15, 1957 motion between substantially the positions shown in Figs. 1 and 3.

Cooperating clamping blocks 28 and 30 are carried by the jaw members 10 and 12 respectively, and these blocks have concave serrated gripping surfaces 32 and 34. The serrated jaw faces 32 and 34 assure a firm grip on a workpiece such as the nut 36 illustrated by way of example in Fig. l, and the concave conformation of the gripping surfaces enables the jaws to adapt themselves more readily to dilferent sizes and shapes of workpieces.

Manifestly, the jaw 12 rocks on the pivot 14 between the open and closed positions shown in the drawings. The handle 18 preferably is made in solid cast form, and the forward end thereof is provided with a longitudinal slot 38 (Fig. 3) which receives the jaw 12, and the pivot 20 bridges the slot 38 and loosely engages the jaw sothat it is free to oscillate on the pivot.

In order to operate the jaws 10 and 12 in use, the fixed handle 16 is connected to the movable handle 18 by a pair ofextensible telescoping members 40 and 42. The member 40 is tubular in form and formed with longitudinal slots 44 to provide flexible elements 46 which collectively define a collet. Both the member 42 and the inner surfaces of the collet elements 46 preferably are provided with essentiallyfine transverse serrations which interlockingly'engage when the elements 46 are pressed against the member 42 to hold the two members 40 and 42 securely against relative sliding motion. When relaxed or unstressed, the collet elements 46 are released from the member 42 so that the two members 40 and 42 are free to slide relative to each other. In this connection, it will be observed, however, that the collet ele ments 46 are formed with internal shoulders 48 and the telescoping member 42 has an enlarged head portion 50 at the inner end thereof which seats on the shoulders 48 to limit outward or separating movement of the members 40 and 42. A spring 52 within the member 40 bears against the head Ell and urges the members 40 and 42 apart. At its forward'end the member 40 extends into .a recess 54 provided in the handle 18 and the portion thereof disposed within the recess is secured to the bandle by a pivot 56. On the other hand, the telescoping member 42 is formed at the rearward end thereof with a swivel connection 58 that is received between the flanges 22 and 24 of the fixed handle 16 and is connected to the handle by a pivot 60.

When the movable handle 18 is opened as shown in Fig. 2, the telescoping members 40 and 42 pull apart as far as possible and thereafter act through the handle 18 and the pivot connection 20 to rock the jaw 12 about the pivot 14 so as to separate or open the jaws 10 and 12. Conversely, when the movable handle 18 is swung to the to overcome any normal resistance of the jaw 12 to rock i on the pivot 14. Thus, if there is no workpiece between the jaws 10 and 12, the jaws are fully closed as shown in Fig. 3. nut 36 is inserted between the jaws ltl and 12, the jaw 12 tends to close until it engages and tightly grips the workpiece. After the jaw 12 engages the workpiece 36, the

. latter of course preventsfurther closing movement of the jaw, and continued closing movement of the movable handle 18 is permitted by telescoping movement of the member 42 into the companion member 40 against the action of spring 52. In this connection it will be observed that a relatively shorter length of the member 42,

On the other hand, if a workpiece such as the extends from the collet 40 in Fig. l which shows a workpiece 36between the jaws and 12 than in Fig. 3 which shows the jaws closed upon each other.

In order to assure a uniformly tight grip of the jaws 10 and 12 on the workpiece disposed therebetween regardless of the size or shape of the workpiece and to lock the jaws securely in the clamped position, a collet sleeve or collar 62 is provided around the elements 46 of the telescoping member 40. As perhaps best shown in Fig. 2, the clamping elements 46 have tapered external surfaces 64 at the distal ends thereof and the collet sleeve 62, which otherwise fits snugly and slidably on the member 40, has a correspondingly tapered inner surface 66 which seats against the tapered ends of the elements'46 when the sleeve is advanced or moved forwardly onthe member 40 and wedges orpresses the elements 46 inwardly into clamping engagement with the member 42. The transverse serrations on the inner surfaces ofthe clamping elements 46 and on the member 42 interlock thereafter to prevent further relative telescoping movement between the members 40 and 42. Motion transmitting means in the form of links 68 and 70 at opposite sides of the handle 18 and of the collet sleeve 62 are fastened to the handle at the forward ends thereof by a common pivot 72 and at'the rearward end thereof to the collet sleeve by pivot studs 74 and 76. The studs 74 and 76 are here shown integral with the sleeve 62 and after the links 68 and 70 are journaled on the studs 74 and 76, the latter are upset in any suitable or conventionalmanner to provide retaining flanges 78 and 80.

It is significant in the form of the invention here shown that the pivot 72 is disposed between the pivots and 56 as the unique relationship of these pivots causes the links 68 and 70 to tighten the collet sleeve 62 on the clamping element 46 automatically when the movable handle 18 is closed and to loosen the collet sleeve from the clamping element automatically when the handle 18 is opened, viz., separated from the fixed handle 16. A stop 82 in the form of a pin extends transversely through the handle 18 and projects therefrom on opposite sides thereof to engage the links 68 and 70 as shown in Fig. 1 when the handle 18 is fully closed and thus limits closing movement of the handle. Also, it should be noted that as'the stop 82 moves into engagement with the links 68 and 70, the pivot 56 moves to'an overcenter position, i. e., it moves below a line interconnecting the pivots 20 and 60.

The overcenter position of the pivot 56 locks the collet sleeve 62 on the clamping element 46 and thus holds the jaws 10 and 12 securely in clamping engagement with a workpiece.

A device of this type, in order/to be competitiveon the market, must be essentially inexpensive to manufacture and this means that careful machining work to close tolerances must be eliminated. All of the parts preferably are made inexpensively from die cast or stamped sheet the fingers exceedingly tightly. Otherwise, relatively great pressure exerted on the jaws by the workpiece, such as might occur when loosening or tightening a nut for example, reacts through the handle 18 and telescopes the member 42 into the member 40 thus permitting the jaws to open and release the work. This means that the links 68 and 70 must tighten the collet 62 on the clamping element 46 at exactly the right moment in the closing action of the pliers, and that they must hold the collet sleeve on the clamping element with precisely the right pressure 'in order to assure proper operation of the device. If the corresponding to the stud 76 of the toggle pliers.

with requisite pressure when the handle 18 is closed.

bleed.

'the adjusted position.

collet sleeve :62 is not forced against the clamping 'element 46 with sufiicient pressure, the telescoping members 40 and 42 are not held tightly enough and the jaws 10 and 12 will open under pressure. On the other hand, if the collet sleeve 62 engages the clamping element 46 with too much pressure, the pliers are too hard to operate both during closing and on opening the device.

According to the present invention, the pivot 72 is eccentric to permit a precise adjustment of the collet sleeve 62 to compensate in every instance for variations in manufacturing tolerances. As shown in Fig. 5, the pivot 72 is formed with an enlarged head 84 which overlies the link 70 and a knurled or serrated cylindrical portion or embossment 86 which fits within an opening 88 provided in the link 70. At the other end thereof the pivot is formed with a smooth surfaced portion 90 that is received within an opening 92 provided in the companion link 68. Intermediate the pivot portions 86 and 9D, is a portion 94 and the portion 94 extends through an opening 96 in the handle 18. Of particular significance is the fact that the intermediate pivot portion 94 is eccentric with respect to the portions 86 and 90 so that rotation of the pivot 72 moves the links 68 and 70 forwardly or rearw'ardly any desired amount within the throw distance of the eccentric portion 94. In this manner the colletsleeve 62, which is carried by the links 68 and 70, can be ad justed longitudinally of the telescoping members 40 and 42 and by reason of such adjustment can be made to engage the clamping'element 46 at the proper time and In order to hold the pivot 72 securely in a selected adjusted position, the opening 88 is provided with serrations which receive and interlock with the external serrations on the pivot portion 86. Alternatively, the pivot can be made of a material harder than the link 70 so that the serrations on the portion 86 bite into and therefore cut their own serrations in the opening 86 when the parts are assem- In' any event, however, the pivot 72 is rotatably adjusted with the serrated portion 86 backed away and disengaged from the link 70, and after the proper rotative adjustment has been made, the serrated portion 86 is pressed into the opening 88 to hold the pivot securely in Thereafter, a snap ring 98 is engaged in a groove 100 provided in the distal end of the pivot which projects beyond the link 68 to hold the parts properly assembled.

Figs. 7 and 8 illustrate the manner in which the principles of this invention can be adapted to a bench clamp. Many parts of the fixture are identical in construction and operation to corresponding parts of the toggle pliers hereinabove described. Accordingly, the corresponding parts of the two devices are identified by the same reference' numerals.

'More specifically, the clamping fixture has a pivoted clamping jaw 12 which, in the form of the invention here shown, is somewhat longer than the jaw of the toggle pliers but it operates in the same manner and serves the same purpose as the movable jaw of the pliers. The clamping jaw 12 is fastened to a fixed base 102 by a pivot 14 and an operating handle 18 is fastened to the clamping jaw 12 by a pivot 20. Telescoping members 40 and 42 are fastened to the operating handle 18 and to the base 102by pivots 56 and respectively, and a pair of links 68 and 70 aredispcsed on opposite sides of the handle 18 and of a collet sleeve 62 which operates the clamping elements (not shown) 'of the telescoping member 40. The forward ends of the links 68 and 70 are fastened to the, handle 18 by an adjustable eccentric pivot 72, and the rearward ends thereof are fastened to the collet sleeve 62 by integral studs. One of these stud pivots 74 is shown, and it will'be understood that the other link 70 is fastened to the opposite side of the" collet sleeve by a pivot stud A stop 82 limits downward clamping ovement of the handle 18.

'The base or mounting member 102' may assume any the jaw 12.

conventional size or shape. However, it preferably is fashioned in some manner which permits it to be fastened conveniently to a bench or other mounting surface 104. The particular mounting here shown is formed of sheet metal and is generally channel shaped in transverse section so that the jaw 12 and the telescoping member 42 can be pivoted between the opposite upstanding flanges thereof. The mounting 102 is here shown fastened securely to a bench 104 by screws 106 and 108.

A clamping block 110 suitable for'engaging and holding a particular workpiece 112 is here shown fastened to Manifestly, it may be necessary to modify the size and shape of the clamping block 110 with difierent types and sizes of workpieces. The workpiece 112 here shown is simply clamped downwardly against the bench 104 by the jaw 12 as shown in Fig. 8. However,

it will be readily apparent that the fixture here shown can be adapted for other types of work holding devices conventionally used for this purpose.

In operation, the handle 18 is raised to disengage the clamping jaw 12 from the work 112 as shown in Fig. 7. When the jaw 12 is raised in this manner the workpiece 112 can be easily removed from the bench 104or placed center position, the jaw 12 is clamped securely against the work and is held positively in the clamped position by the toggle mechanism of the device.

What is claimed is:

1. In an apparatus of the character described, a mounting, a pivoted clamping jaw on said mounting, actuator means for said jaw, a pivot connecting said actuator means to said jaw, extensible rigid members, a pivot connecting one of said members to said actuator means, a pivot connecting the other of said members to said mounting, means coactive with said members engageable therewith to hold the same in a selected adjusted position and releasable therefrom to permit longitudinal adjustment thereof, and motion transmitting means pivoted to said last mentioned means and to said actuator means operable to disengage said means from said extensible membars by pivotal movement of said actuator in one direction and to lockingly engage said means with said adjustable members by pivotal movement of said actuator in the opposite direction.

2. In a device of the character described, a mounting member, a clamping jaw pivoted to said mounting member, a handle, a pivot connecting said handle to said clamping jaw, telescoping members, one member being in the form of a collet and said collet being arranged to clampingly engage the other of said members, a pivot connecting one of said telescoping members to said handle, a pivot connecting the other of said telescoping members to said mounting member, a tapered collar slidable on said collet and adapted to clamp the latter on said other member, and collar actuating means pivoted to the collar and to said handle for moving said collar automatically into clamping engagement with said collet when said handle is pivoted in the direction of said mounting member.

3. A self-adjusted toggle clamp comprising a pair of pivotally connected jaws, a fixed handle on one jaw, a movable handle, a pivot connecting said movable handle to the other of said jaws, a pair of longitudinally adjustable members, a pivot connecting one member to said movable handle, a pivot connecting the other member to said fixed handle, means including a longitudinally adjustable element engageable with and releasable from said members for holding the latter in a selected longitudinally adjusted position, and motion transmitting means pivotally connected to said element and to said movable handle operable to engage and release said element when said movable handle is rocked on said first mentioned pivot.

4. A self-adjusting toggle clamp comprising a pair of pivotally connected jaws, a fixed handle on one jaw, a movable handle, a pivot connecting said movable handle to the other of said jaws, telescoping members, one memher being in the form of a collet and said collet being arranged to clampingly engage the other of said members, a pivot connecting one member to said movable handle, a pivot connecting the other member to said fixed handle, a tapered collar slidable on said collet and adapted to clamp the latter on said other member, and collar actuating means pivoted to the collar and to said movable handle, the pivot connecting said links to said handle having an eccentric portion in said handle and a peripherally serrated portion in one of said links, said links having internal serrations complementing and interlock ing with those on said pivot so as to hold the'eccentric portion of the latter in a selected rotatably adjusted position, and said pivot being rotatably adjustable to vary the distance between the pivots connecting said links to the mentioned parts of the pliers.

5. A self-adjusting toggle clamp comprising a pair of pivotally connected jaws, a fixed handle on one jaw, a movable handle, a pivot connecting said movable handle to the other of said jaws, telescoping members, one member being in the form of a collet and said collet being arranged to clampingly engage the other of said members, a pivot connecting one member to said movable handle, a pivot connecting the other member to said fixed handle, a tapered collar slidable on said collet and adapted to clamp the latter on said other member, and collar actuating means pivoted to the collar and to said movable handle.

6. A self-adjusting toggle clamp comprising a pair of pivoted clamping members, a fixed handle on one clamping member, a movable handle, a pivot connecting said movable handle to'the other of said clamping members, extensible and retractible parts, one part being in the form of a collet and said collet being arranged to clampingly engage the other of said parts, a pivot connecting one part to said movable handle, a pivot connecting the other part to said fixed handle, a tapered collar slidable on said collet and adapted to clamp the latter on said other part, collar actuating means pivoted to the collar and to said movable handle, and adjustable means for varying the distance between the pivots connecting said links to said collar and to said handle.

7. A self-adjusting toggle clamp comprising a pair of pivotally connected jaws, a fixed handle on one jaw, a movable handle, a pivot connecting said movable handle to the other of said jaws, telescoping members, one memberbeing in the form of a collet and said collet being arranged to clampingly engage the other of said members, a pivot connecting one member to said movable handle, a pivot connecting the other member to said fixed handle, a tapered collar slidable on said collet and adapted to clamp the latter on said other member, and collar actuating means pivoted to the collar and to said movable handle, at least one of the pivots connecting said links having an eccentric portion and the arrangement being such that rotation of said eccentric portion varies the distance between the pivots which connect said links to the mentioned parts of the clamp.

8. A self-adjusting toggle clamp comprising relatively movable jaws, a fixed element on one jaw, a movable handle, a pivot connecting said movable handle to the other of said jaws, a pair of telescoping members, one member including a collet arranged to clampingly engage the other of'said members, a pivot connecting one member to said movable handle, a tapered collar slidable on said collet and adapted to clamp the latter on said other member, collar actuating means pivotally connected to Said collar and to said movable handle, 'the pivot connecting "said links to said handle having an eccentric portion and said portion being rotatably movable toadjust said collar longitudinally on said collet, and means including interfitting serrations holding said eccentric portion in a selected, rotatably adjusted position.

9. A self-adjusting toggle clamp comprising relatively movable jaws, a fixed handle on one jaw, a movable handle, a pivot connecting said movable handle to the other of said jaws, a pair of telescoping members, one member including a collet arranged to clampingly engage the other of said members, a pivot connecting one member to said movable handle, a tapered collar slidable on said collet and adapted to clamp the latter on said other member, collar actuating means p-ivotally connected to said collar and to said movable handle, the pivot connecting said links to said handle having an eccentric portion, and said portion being rotatably movable to adjust said collar longitudinally on said: collet, and means for holding said eccentric portion in a selected, rotatably adjusted position.

10. A self-adjusting toggle clamp comprising a pair of relatively movable clamping members, a fixed mounting on one of said clamping members, a movable handle, a pivot connecting said movable handle to the other of said clamping members, a pair of extensible and retractible parts, one part including a collet arranged to clampingly engage the other of said parts, a pivot connecting one p'artto said handle, a pivot connecting the other part to said mounting, a collar slidable on said collet adapted to clamp the latter on said other part, collar actuating means connected to said collar and to said handle including a pivot connection to said handle, and adjustable means for adjusting said collar longitudinally on and relative to said collet.

11. A toggle linkage for a clamping device of the type having a fixed part and a relatively movable part comprising a handle adapted for pivotal connection to said movable part, telescoping members, a pivot connection on one of said members adapted for pivotal attachment to said fixed part, a pivot connecting the other of said members to said handle, one member including a collet arranged to. clampingly engage the other of said members, a collar slidable on said collet and adapted to clamp the latter on said other member, collar actuating means pivotally connected to said collar and to said handle for moving said collar automatically into and out of clamping engagement with said collet by actuation of said handle, and adjustable means for adjusting said col- 'lar longitudinally on and relative to said collet.

12. A toggle linkage for a clamping device of the type having a fixed part and a movable part comprising a handle adapted for pivotal connection to said movable part, telescoping members, a pivot connection on one of said members adapted for pivotal attachment to said fixed part, a pivot connecting the other of said members to saidhandle, one member including a collet arranged to clampingly engage the other, of said members, a collar slidable on said collet and adapted to clamp the latter on said other member, collar actuating means pivotally conne'cted to said collar and to said movable handle, the pivot connecting said links to said handle having an .8 eccentric portion and said portion being rotatably movable toadjustsaid collar longitudinally on and relative to said collet, and means including interfitting serrations on said pivot and said links holding said eccentric portion ina selected rotatablyadjusted position.

. i 13. A clampingdevice comprising a mounting, a movable clamping jaw on said mounting, actuator means for said jaw, a pivot connecting said actuator means to said jaw, a pair of extensible rigid members, a pivot connecting one of said members to said actuator means, a pivot connecting the other of said members to said mounting, means coactive with said members engageable therewith to hold the same in a selected adjusted position and releasable therefrom to permit longitudinal adjustment thereof, and pivoted motion transmitting means connected to said last-mentioned means and to said actuator means operable to disengage said means from said extensible members by pivotal movement of said actuator in one direction and to lockingly engage said means with said adjustable members by pivotal movement of said actuator.

in the opposite direction.

14. A toggle linkage for a clamping device having a fixed mounting and a movable clamping jaw comprising a handle adapted for pivotal connection to said jaw, a pair of extensible rigid members, a pivot connection on one of said members adapted for pivotal attachment to said fixed mounting, a pivot connecting the other of said members to said handle, means coactive with said members engageable therewith to hold the same in a selected adjusted position and releasable therefrom to permit longitudinal adjustment thereof, and pivoted motion transmitting means connected to said last-mentioned means and to said handle operable to disengage said -means from said extensible, members by movement of said handle in one direction and to lockingly engage said means with said adjustable members by pivotal movement of said handle in the opposite direction.

15. A toggle linkage for a clamping device of the type -having a fixed part and a movable part comprising a handle adapted for pivotal connection to said movable part, a pair of telescoping members, a pivot connection on one member adapted for pivotal attachment to said fixed part, a pivot connecting the other of said members to said handle, one member including a collet arranged to clampingly engage the other of said members, a collar slidable on said collet and adapted to clamp the latter on said other member, and pivoted collar actuating means connected to said collar and to said handle for moving said collar automatically into and out of clamping engagement with said collet by actuation of said handle.

References Cited in the file of this patent UNITED STATES PATENTS 732,858 Irland July 7, 1903 823,166 Glover June 12, 1906 2,397,239 Brown Mar. 26, 1946 2,454,744 Peterson et al. Nov. 23, 1948 2,531,285 Manspeaker Nov. 21, 1950 2,584,952 Westerman et a1. Feb. 5, 1952 FOREIGN PATENTS 378,125 Germany July 3, 1923 

